Had some example comparisons, but apparently AVIF uploads don't work on forums atm. On the AV1 and codec yeah hopefully, but for now it still needs to gain a better footing as a standard like even MS Paint doesn't allow AVIF export yet though it can import AVIF images fine and pretty common issue with software atm non existent or partially supported for the time being.
Sure, if it's for comparing quality of lossy compression.
If it's for comparing size of lossless files, you can just tell us the results.
Paint supports saving HEIC, but not AVIF or JPEG XL.
But considering how long it took MS to add PNG support in the first place, I wouldn't expect them to support the updated PNG spec anytime soon, perhaps in Windows 15 in 2038?
Not that I think that's a problem though, as anyone can still read AVIF files, and if you're making them, you're not working with MS Paint. Pretty much "anything" support AVIF at this point, incl. Photoshop, Lightroom, GIMP, Darktable, Krita, Paint.NET, ImageMagick, etc.
IMO websites should only use 3 (or 4) formats:
- For legacy support use Jpegli encoded JPEGs and Gifsickle encoded Gifs.
- Widest support (for now) and good low quality (low BPP) is avif (both static and animated) ideally encoded using the IQ Tune option in libavif.
- Highest quality and features is JXL for transparency, progressive decoding and animation, although browser support is hampering it big time (doesn't help that low BPP is more desireable by most websites so that's the appealing choice).
I don't know how old browsers you would recommend people use, but anything except Edge has supported AVIF for years. So I would say anything that's probably is used online supports AVIF.
Gif is a horrible format I wish was abandoned back in 1995.
Lossless compression with transparency is very relevant for anything GUI related (incl. applications and games).
For photos, those who don't need any kind of raw format or do any future heavy editing, will probably do fine with lossy compression like JPEG. But it is worth noting that compression size isn't everything, as different format results in different kinds of compression artifacts;
Some years ago I looked into using JPEG vs. WEBP (and probably others) for textures. It turns out that for ground textures, the compression artifacts of JPEG kind of works in its favor, as it blends in with the graininess of the texture up to a point (as long as you can't see the blockyness). I don't remember now the quality level I considered the sweet-spot (but I probably have it somewhere in my projects). When it comes to smoother surfaces, and probably normal maps etc., blurry artifacts are usually more desirable than grainy/blocky artifacts.